Cut-off die set

ABSTRACT

A ram-driven cut-off die set of the double-cut type in which sections of tubing are successively severed from a continous length of tubing by a notching cut followed by a severing cut wherein improved means are provided for mounting and guiding the notching blade in its notching movement. The improved mounting means comprises an upper shaft positioned over the tube path and extending from one side to the other side of the path, a lower guide shaft positioned totally on the one side of the tube path, and a cross slide having a relatively long upper portion slidably journalled on the upper shaft and a relatively short lower portion journalled on the lower guide shaft to maximize the magnitude of the journalling support provided to the notching blade as it makes its reciprocal movement across the tube path to accomplish the notching cut.

This application is a division, of application Ser. No. 129,429, filed11/25/87, now U.S. Pat. No. 4,766,792.

FIELD OF THE INVENTION

This invention relates to tube cutting apparatus of the type used tocontinuously lengths of tubing from tubing or other elongated stockcontinuously emanating from a mill in the which the apparatus includes acut-off die set operated by a ram and wherein the die set is caused tobe clamped to the tubing during the severing operation and wherein thesevering operation is carried out by a vertically reciprocating cut-offblade. More particularly, the present invention is drawn to animprovement in the notching mechanism which is used in conjunction withthe cut-off die set to notch the upper periphery of the tubing justprior to severing by the main cut-off blade.

BACKGROUND OF THE INVENTION

In cut-off die sets of the double cut or pre-notching type, a notchingblade is reciprocated across the upper periphery of the tubing after thetubing is clamped within the die set clamping jaws and just prior todescent of the main cut-off blade or guillotine. The pre-notchingeliminates the cusping or dimpling of the tubing to a large extent tothe point that subsequent reshaping of the ends of the severed length oftubing is not normally required. Whereas this general arrangement of apre-notching cut followed by a final severing operation is generallysatisfactory in producing tubing which does not require any subsequentreshaping, it is imperative that the notching blade be mounted in such away that its reciprocating notching movement is precise and firmlysupported throughout the movement of the blade.

SUMMARY OF THE INVENTION

Briefly summarized, the invention is an adjustable notching blade holdermounted to a horizontally reciprocating cross-slide assembly four use ina tube cutting apparatus of the double cut type, wherein the notchingblade is positioned perpendicular to the tube path and adjacent to theouter surface of the tubing to perform either a "pull-across" or"forward thrust" notching motion.

In general, the adjustability is accomplished by a vertical guidewayestablished on the cross-slide assembly combined with a means ofadjusting the vertical position of the notching blade holder on saidguideway, further including a means for retaining the notching bladeholder in any position of vertical adjustment.

In the preferred form a set of L-shaped brackets are mounted to thecross slide forming a vertical guideway, each bracket having a lugportion at the lower end extending outward from the cross slide at rightangles. The notching blade holder is retained in the vertical guidewayby means of a slide member contained between the projections of theL-shaped brackets. A pair of first and second vertically extendingparallel screws are the means for allowing vertical adjustment of thenotching blade holder. The adjustment screws threadaby engage thenotching blade holder at their upper ends, the head portions of thefirst and second screws engage the lug portions of the bracketsextending outward from the cross-slide assembly.

The adjustment screws and lug portions of the brackets also perform themeans for locking the notching blade assembly in position. The lockingmeans is accomplished by said first screw bearing downwardly against theupper surface of the first bracket lug, and said second screw passingthrough a bore located in the second bracket lug and bearing upward uponthe lug undersurface. The combination of parallel screws acting uponopposite bearing surfaces causes the notching blade holder to be firmlyretained in the set position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an end elevational view of a cut-off die set according to theinvention;

FIG. 2 is a top view of the invention cut-off die set with portionsremoved for clarity of illustration;

FIG. 3 is a cross-sectional view taken on line 3--3 of FIG. 2; and

FIG. 4 is an exploded fragmentary view of the mounting means for thenotching blade of the invention cut-off die set.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention cut-off die set 10 is adapted to be employed in a tubecutting apparatus and is slidably movable along a set of rails 11extending from the tube-forming mill. The tube cutting apparatusnormally includes a swinging or reciprocating ram mechanism which servesto operate the cut-off die set 10. In die sets of the general type withwhich the present invention is concerned, the cut-off die set ispositioned to receive the tubing as it emanates from the processingfabrication mill and the ram mechanism operates to cause the clampingjaws within the die set to be operated to clamp the die set to therapidly moving tubing. The die set, clamped to the moving tube, movestogether with the tube along the rail set extending from the mill. Theram mechanism then causes the notching blade to make a notching cut inthe upper periphery of the tubing whereafter the main cut-off blade islowered to sever a length from the moving tube. Following the finalsevering cut, the ram mechanism, then operating in a reverse manner,first causes retraction of the main cut-off blade and the notching bladeand then unclamping of the die set from the tube section as the cut-offdie set approaches the end of its travel on the rail set. The cut-offdie set is then returned to its initial position on the rail setpreparatory to initiation of a new cut-off cycle.

Cut-off die set 10 includes an upper platen or shoe 12 and a lowerplaten or shoe 14.

Upper platen 12 overlies the tube path 16 and includes three guide rods18, 20 and 22 extending downwardly from spaced locations on theunderside of platen 12. Guide rod 18 is positioned on the lefthand ornear side of tube path 16 and guide rods 20 and 22 are positioned at thefront and rear of the cut-off die set respectively on the righthand orremote side of tube path 16. A die jaw cam 24 extends downwardly fromupper platen 12 generally between guide rods 20 and 22 and a cam guide26 extends downwardly from upper platen 12 adjacent the rear edgethereof and on the near or lefthand side of tube path 16.

A plurality of guide sleeves or bushings 28, 30 and 32 upstand fromlower platen 14 and respectively telescopically receive the lower endsof guide rods 18, 20 and 22 so as to guide upper platen 12 in itsreciprocal vertical movement relative to lower platen 14 during the tubesevering operation.

The tubing 34 emanating from the tube forming mill is caused to beclamped to the die set 10 by means of a pair of die jaws 36 and 38 eachhaving a complimentary inner radius contour 40 and 42, respectively,complimentary to the tube contour when the clamping jaws 20 and 22 arecaused to advance toward each other so as to engage tube 34. Thereciprocal clamping and disengaging movement of die jaws 36 and 38 isproduced by sliding movement of an upper die jaw holder 44 and a lowerdie jaw holder 46 slidable on each other. The die clamping jaws 36 and38 are adapted to be reciprocated towards and away from each other insynchronism with the vertical movement of the upper platen relative tothe lower platen by coaction of die jaw cam 24 passing between a pair ofclamping rollers 48 and 50 carried respectively by the upper die jawholder 44 and lower die jaw holder 46. The manner in which the cam 24coacts with the rollers 48 and 50 to move the die jaws 36 and 38 intoand out of clamping engagement with tube 34 will not be furtherdescribed since this mechanism is known and is not part of the presentinvention. Further details of a mechanism of this type may be found inU.S. Pat. Nos. 4,108,029 and 4,294,147, both assigned to the assignee ofthe subject application.

A main cut-off blade or guillotine 52 is mounted in a blade holderassembly 54 which in turn is secured to the underside and extendsdownwardly from upper platen 12. Die jaws 36 and 38 are slottedtransversely at 55 relative to the tube axis to provide a clearancespace through which the blade 52 will pass upon the ram operatingmechanism reciprocating the upper platen 12 downwardly sufficiently topass through the plane of the tube.

A notching mechanism seem generally at 56 operates to provide a notchingcut in the upper periphery of the tube prior to the downward severingmovement of the guillotine 52 so as to preclude the necessity of furtherworking of the severed tube section following the severing operation.The present invention relates primarily to the improved notchingmechanism 56. Notching mechanism 56 includes a support bracket 58, asupport bracket 60, a support bracket 62, an upper guide shaft 64, alower guide shaft 66, a cross slide 68, and a notching or scarfing bladeassembly 70.

Support bracket 58 is L-shaped in cross section and upstands rigidlyfrom lower platen 14 at the nearside of tube path 16 adjacent thelefthand edge 14a of the lower platen 14.

Support bracket 60 is positioned on the upper end of bushing 32 andincludes a forwardly extending journal portion 60a.

Bracket 62 upstands rigidly from lower platen 14 at a location betweenbracket 58 and tube path 16.

Upper guide shaft 64 is secured at its near or lefthand end in supportbracket 58 and at its remote or righthand end in journal portion 60a ofsupport bracket 60. Upper guide shaft 64 thus extends across the tubepath 16 from a location on the nearside of the tube path to a locationon the other or remote side of the tube path.

Lower guide shaft 66 is positioned parallel to, below, and in the samevertical plane as upper guide shaft 64 with its lefthand or near end 66mounted in support bracket 58 and its righthand or other end secured insupport bracket 62. Lower guide shaft 66 is thus positioned totally onthe near or lefthand side of tube path 16.

Cross slide 68 includes a relatively long upper portion 68a and arelatively short lower portion 68b. Upper guide shaft 64 passes througha through-bore 68c in upper cross slide portion 68a and lower guideshaft 66 passes through a through-bore 68d in lower cross slide portion68b. A pair of bearings 72 and 74 at the opposite ends of through-bore68c facilitate the journalling of upper guide shaft 64 in through-bore68c and a pair of bearings 76 and 78 facilitate the journalling of lowerguide shaft 66 in through-bore 68d.

A roller cam follower 80 secured by a screw 82 to cross slide 68 guidesin the curvilinear cam track 26a of cam 26 to reciprocate cross slide 68back and forth on guide shafts 64 and 66 in response to relativevertical movement between upper platen 12 and lower platen 14. Upperguide shaft 64 is hollow and receives a lubricating fitting 84 tofacilitate the introduction of lubricant into the sliding interfacebetween through-bore 68c and upper cross slide portion 68a. Similarly,lower guide shaft 66 is hollow and receives a lubricating fitting 86.Nuts 88 and 90 on the respective left or near ends of shafts 64 and 66facilitate the mounting of the shafts in their respective brackets.

Notching blade assembly 70 includes a notching or scarfing blade 92,blade clamps 94 and 96, a blade holder 98, guide brackets 100 and 101,and a slide 102.

Blade 92 is clamped to the righthand or free end of blade holder 98 byscrews 104 which secure the blade to the free end of the blade holder insandwich fashion between clamps 94 and 96. Thus secured, notching blade92 lies in the plane of cut-off blade 52 and in alignment with slot 55in die jaws 36 and 38

Brackets 100 and 101 are secured by screws respectively in a pair ofparallel vertical grooves 68e formed in the forward face of cross slide68. Brackets 100 and 101 are L-shaped in cross section and are mountedto the forward face of cross slide 68 in confronting relation to eachother so as to define a guide channel 106 for vertical sliding receiptof slide member 102. A vertical rib 98a on the rear face of blade holder98 passes through the confronting inturned edges of brackets 100 and 101for engagement with the front face of slide 102. Blade holder 98 issecured to slide 102 by suitable screws 108.

A first adjustment screw 110 is threadably engaged at its upper end in athreaded bore in blade holder 98 with its head 110a positioned on top ofand pressing against a foot portion 100a of bracket 100, and a secondadjusting screw 112 is positioned with its upper end threadably engaginga threaded bore in blade holder 98 and with its lower end passing freelythrough a foot portion 101a of bracket 101 to position its head portion112a on the underside of foot portion 101a. Screw 110 is adjusted by anAllen head wrench passed upwardly through a bore 100b in foot portion100a of bracket 100 and screw 112 is adjusted by an Allen head wrenchreceived directly in a suitable socket in head 112a. It will be seenthat selective adjustment of screws 110 and 112 selectively varies thevertical position of blade holder 98, and thereby blade 92, with respectto cross slide 68 and provides a firm, non-cocking mounting of the bladeon cross slide 68 irrespective of the position of vertical adjustment ofthe blade on the cross slide.

The described mounting arrangement for the notching or scarfing bladewill be seen to provide a firm positive support for the blade throughoutits reciprocal motion to accomplish the notching stroke. Specifically,the described arrangement with the upper guide shaft extendingcompletely across the path of the tubing in cooperation with the lowerguide shaft positioned to one side of the tube path maximizes thejournalling support of the cross slide and thereby maximizes thestability of the notching blade during its reciprocal movement. Theprovision of a positive and precise movement of the notching blade isimportant to the successful operation of a double-cut apparatus of thetype disclosed since the synchronization between the notching blade andthe guillotine or severing blade is critical. Specifically, since thenotching blade and cut-off blade are moving in a common plane, and sincetime is of the essence in making a flying cut of the type involved inthe double-cut apparatus, as the notching blade is moving from right toleft across the upper periphery of the tube to make the notching cut theguillotine has already begun its downward movement to accomplish thesevering cut. In actuality, the lefthand lower bevelled edge 52a of theguillotine passes precariously close to the righthand bevelled edges 98band 92a of the blade holder and notching blade respectively so that anycocking or misalignment of the blade holder or notching blade couldresult in interference between the blade holder and notching blade andthe descending cutting edge of the guillotine with disastrous results.The described support mechanism for the notching blade allows thevarious movements of the notching blade and guillotine to be preciselytimed with the assurance that the exquisite clearances programmedbetween the guillotine and the notching blade will be maintained inactuality and over sustained periods of use of the apparatus.

Although a preferred embodiment of the invention has been illustratedand described in detail, it will be apparent that various changes may bemade in the disclosed embodiment without departing from the scope orspirit of the invention.

We claim:
 1. In a cut-off die apparatus for tubing of the double cuttype including means for moving the tubing along a feed path, a platenpositioned at one side of the feed path, a pair of die jaws movablymounted on the platen for selective movement into clamping relationshipto the tubing as the tubing moves along the feed path, means forperforming a notching cut by a notching blade mounted for reciprocalmovement across the tube feed path, and means for performing a severingcut following the notching cut, the improvement wherein the mountingmeans for the notching blade comprises:(A) a first linear guide meansextending effectively over said feed path and at essentially rightangles thereto and immovably mounted on said platen in a position spacedfrom said die jaws on the side of said feed path opposite said one sidethereof with said jaws positioned between said guide means and saidplaten; (B) a second linear guide means immovably mounted on sd aidplaten below said first linear guide means and at essentially rightangles to said feed path; (C) a cross slide mounted on said first andsecond linear guide means for reciprocal displacement thereover; and (D)means mounting said notching blade on said cross slide for reciprocalmovement therewith across said path.
 2. Apparatus as defined in claim 1wherein said first and second linear guide means are substantiallyvertically spaced from one another.
 3. A cut-off die apparatus forsuccessively severing sections of tubing from a continuous length oftubing from a continuous length of tubing moving along a tube path, saidapparatus comprising:(A) a lower platen positioned below said path; (B)an upper platen positioned above said path over said lower platen andmounted for vertical reciprocal movement relative to said lower platenbetween a raised rest position and a lowered cutting position; (C) upperlinear guide means carried by said lower platen and effectivelyextending horizontally from one side of said path to the other side ofsaid path at a position which is vertically spaced above the lowerplaten and the tube path; (D) lower linear guide means positioned belowsaid upper guide means and on one side of said path; (E) a cross slidemounted for reciprocal horizontal movement on said first upper and lowerguide means; (F) a notching blade mounted on said cross slide andoperative to make a notching cut in the periphery of the tubing inresponse to the reciprocal movement of the cross slide on said guidemeans; and (G) a guillotine blade extending downwardly from said upperplaten in the plane of said notching blade and operative to sever asection to tubing from the tube in response to movement of said upperplaten from its raised position to its lowered position and followingsaid notching cut of said notching blade.
 4. Apparatus as defined inclaim 3 wherein said cross slide engages and is supported by said upperlinear guide means both on said one side and said other side over atleast part of its reciprocal movement.